Bottom Line:
Therefore, the elucidation of their identities and functions is of great interest.Here, we show that matrix metalloproteinases (MMPs) generate a domain (DIII) from the ECM macromolecule laminin-5.Binding of a recombinant DIII fragment to epidermal growth factor receptor stimulates downstream signaling (mitogen-activated protein kinase), MMP-2 gene expression, and cell migration.

fig3: Induction of EGFR tyrosine phosphorylation by rDIII. (A) Incubation of MDA-MB-231 cells with 185 nM rDIII for 5 min (lane 4, top) stimulated phosphorylation of EGFR. There is no EGFR stimulation for the 2-min rDIII sample (lane 3), or the 5-min no ligand control (lane 1). To exclude nonspecific effects due to cross-linking, cells were exposed to BS3 in the absence of ligand (lane 2). To ensure that equal amounts of EGFR protein were loaded, blots were stripped and reprobed with EGFR pAb (bottom). (B) EGFR phosphorylation by 185 nM rDIII (lane 1, top) and 1.7 nM EGF (lane 2) for 5 min in the absence of BS3. For control, ligand was omitted (lane 3), and the loading controls are shown in the bottom panel.

Mentions:
MDA-MB-231 cells treated with rDIII for 5 min in the presence of BS3 showed distinct EGFR phosphorylation (Fig. 3 A). BS3 alone did not induce EGFR phosphorylation. In control experiments without cross-linker, significant EGFR phosphorylation was detected in samples containing rDIII (Fig. 3 B) or EGF, whereas control samples devoid of ligand failed to show EGFR phosphorylation. These data show that rDIII stimulates EGFR phosphorylation.

fig3: Induction of EGFR tyrosine phosphorylation by rDIII. (A) Incubation of MDA-MB-231 cells with 185 nM rDIII for 5 min (lane 4, top) stimulated phosphorylation of EGFR. There is no EGFR stimulation for the 2-min rDIII sample (lane 3), or the 5-min no ligand control (lane 1). To exclude nonspecific effects due to cross-linking, cells were exposed to BS3 in the absence of ligand (lane 2). To ensure that equal amounts of EGFR protein were loaded, blots were stripped and reprobed with EGFR pAb (bottom). (B) EGFR phosphorylation by 185 nM rDIII (lane 1, top) and 1.7 nM EGF (lane 2) for 5 min in the absence of BS3. For control, ligand was omitted (lane 3), and the loading controls are shown in the bottom panel.

Mentions:
MDA-MB-231 cells treated with rDIII for 5 min in the presence of BS3 showed distinct EGFR phosphorylation (Fig. 3 A). BS3 alone did not induce EGFR phosphorylation. In control experiments without cross-linker, significant EGFR phosphorylation was detected in samples containing rDIII (Fig. 3 B) or EGF, whereas control samples devoid of ligand failed to show EGFR phosphorylation. These data show that rDIII stimulates EGFR phosphorylation.

Bottom Line:
Therefore, the elucidation of their identities and functions is of great interest.Here, we show that matrix metalloproteinases (MMPs) generate a domain (DIII) from the ECM macromolecule laminin-5.Binding of a recombinant DIII fragment to epidermal growth factor receptor stimulates downstream signaling (mitogen-activated protein kinase), MMP-2 gene expression, and cell migration.